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A303633 Number of nX5 0..1 arrays with every element unequal to 2 or 3 horizontally or vertically adjacent elements, with upper left element zero. 1
0, 3, 0, 8, 20, 66, 207, 726, 2461, 8538, 29072, 100909, 345464, 1192462, 4104543, 14145598, 48741105, 167919091, 578641035, 1993746222, 6869984946, 23672540436, 81569450595, 281073069448, 968513250894, 3337304064491, 11499656306463 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Column 5 of A303636.
LINKS
FORMULA
Empirical: a(n) = 4*a(n-1) +3*a(n-2) -21*a(n-3) +15*a(n-4) +20*a(n-5) -113*a(n-6) +119*a(n-7) +47*a(n-8) -605*a(n-9) +1543*a(n-10) -410*a(n-11) -2330*a(n-12) +4699*a(n-13) -5222*a(n-14) +1426*a(n-15) +6743*a(n-16) -13402*a(n-17) +8575*a(n-18) +2680*a(n-19) -11720*a(n-20) -5652*a(n-21) +5363*a(n-22) +16884*a(n-23) -3961*a(n-24) +3927*a(n-25) +1752*a(n-26) -7869*a(n-27) +2055*a(n-28) +872*a(n-29) -2059*a(n-30) +338*a(n-31) +346*a(n-32) -322*a(n-33) +74*a(n-34) +159*a(n-35) -165*a(n-36) +47*a(n-37) +15*a(n-38) -6*a(n-39)
EXAMPLE
Some solutions for n=5
..0..1..0..1..0. .0..1..1..0..1. .0..1..0..1..0. .0..1..0..1..0
..1..1..0..0..1. .1..0..0..1..0. .1..1..0..1..1. .1..0..0..1..1
..0..0..1..1..0. .0..1..0..1..1. .0..0..1..0..0. .0..1..1..0..0
..1..0..1..1..0. .0..1..1..0..0. .1..0..1..0..1. .1..0..0..1..1
..0..1..0..0..1. .1..0..1..0..1. .0..1..0..1..0. .0..1..0..1..0
CROSSREFS
Cf. A303636.
Sequence in context: A019691 A192919 A068607 * A167004 A287632 A259346
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 27 2018
STATUS
approved

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Last modified April 14 14:16 EDT 2024. Contains 371665 sequences. (Running on oeis4.)